1. Field of the Invention
This invention relates to data storage systems and, more particularly, to performing backups and restores of data in data storage systems.
2. Description of the Related Art
Backup systems are used to protect data against loss. Typically, a backup system includes software that periodically copies user data to a backup storage device (e.g., such as a tape drive). If data is lost (e.g., due to user error or device failure), the backed-up copy of the data can be retrieved from the backup storage device.
Many organizations implement a network-based backup system in order to ensure that the organization's data is regularly backed up. For example, a company can implement a network-based backup system to ensure that employees' data is backed up on a daily basis. Data that is stored on storage devices connected to the network is then backed up at regular intervals.
A revolutionary growth in the use and distribution of digital media (from audio podcasts to video distribution) now complements the ceaseless growth in digital documents that has persisted for the last decade. Maturation of market models for digital content delivery has enabled the creation of high-value services and products, in which, ever-increasing amounts of digital media are sold to and accumulated by the user. This growth in paid digital content has increased the dollar value of the digital documents stored and retained by the average user, and has thereby increased the demand for backup services.
Unfortunately, the growth in digital content delivery has also created a concomitant growth in the volume of material stored by users, increasing the resources required to perform a backup operation. A large percentage of this volume is composed of what can be called ‘incidental material’, the preservation of which is of no particular importance to the user. Much of this incidental material may be downloaded for one-time use or temporary viewing, or may be freely available on the Internet, such that current backup operation solutions, which indiscriminately include such incidental material in backup operations, waste resources and impose unnecessary costs.